<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>固定定位</title>
    <style>
        .ad{
            width: 60px;
            height: 200px;
            border: 1px solid #000;
            position: fixed;
            right: 20px;
            bottom: 30px;
        }
        .ad a{
            position: absolute;
            right: 2px;
            top: 2px;
        }
        .k{
            width: 100px;
            height: 100px;
            border: 1px solid #00f;
            margin: 20px;
        }
    </style>
</head>
<body>
    <div class="ad">
        <a href="">关闭</a>
    </div>
    <div class="k"></div>
        <div class="k"></div>
</body>
</html>